A paper published in the journal Nature shows a causal relationships between sea birds populations and reef health. A team from Lancaster University has compared reefs in the Chagos archipelago, some surrounding islands that are rat free, and others on which rats have been introduced. The rat free islands have significantly higher populations of sea birds.
The results showed that herbivorous damselfish on reefs adjacent to the rat-free islands grew faster, and fish communities had higher biomass across trophic feeding groups, with 48% greater overall biomass. In addition, rates of two critical ecosystem functions, grazing and bioerosion, were 3.2 and 3.8 times higher, respectively, adjacent to rat-free islands.